Ostomy device

ABSTRACT

Disclosed is an ostomy device with an adhesive wafer for attachment to a skin surface of a user and a collecting bag for collecting output from a stoma. The collecting bag is connected to the adhesive wafer, and the adhesive wafer has a through-going hole for accommodating the stoma of the user. The adhesive wafer includes a backing layer, a first switchable adhesive composition, a second adhesive composition, and a release liner. The first adhesive is contained in a recess in the device. The first switchable adhesive composition comprises a polymer and a switch initiator, and can be switched from a first liquid state to a second adhesive state by activation of the switch initiator.

Disclosed is an ostomy device with an adhesive wafer for attachment to askin surface of a user and a collecting bag connected to the adhesivewafer. The adhesive wafer includes a backing layer, a first switchableadhesive composition, a second adhesive composition, and a releaseliner. The first switchable adhesive is contained in a recess in thedevice.

BACKGROUND

In connection with surgery for a number of diseases in thegastro-intestinal tract, one of the consequences in many cases is thatthe patient is left with an abdominal stoma, such as a colostomy, anileostomy or a urostomy, in the abdominal wall for the discharge ofvisceral contents. The discharge of visceral contents cannot beregulated at will. For that purpose, the user will have to rely on anappliance to collect the material emerging from such opening in a bag,which is later emptied and/or discarded at a suitable time. Ostomyappliances are typically attached to the skin of the ostomy user bymeans of an adhesive wafer on the ostomy appliance.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawings are included to provide a furtherunderstanding of embodiments.

FIG. 1 illustrates an embodiment of an ostomy device in cross-section,

FIG. 2 shows another embodiment in cross-section,

FIG. 3 shows yet an embodiment of in cross-section,

FIG. 4 shows the embodiment of FIG. 2 applied to the skin surrounding astoma

FIG. 5 shows an embodiment in cross-section,

FIG. 6 shows an embodiment in cross-section and

FIG. 7 shows an embodiment in cross-section.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments provide an ostomy device including an adhesive wafer forattachment to a skin surface of a user, and a collecting bag connectedto the adhesive wafer. The collecting bag is suitable for collectingoutput from the stoma of the user. The adhesive wafer has athrough-going hole for accommodating the stoma of the user. In this way,the output from the stoma ends up in the collecting bag. The adhesivewafer includes a backing layer, a first switchable adhesive composition,a second adhesive composition, and a release liner. The first switchableadhesive composition is accommodated in a recess in the device.

In embodiments, the adhesive wafer will have a proximal (“skin-facing”)surface, which faces the skin of the user during use, and a distal(“non-skin-facing”) surface, which faces away from the user's skinduring use. Before use, the proximal surface of the adhesive wafer canbe covered by a release liner, which is releasably attached to theadhesive. The release liner can be removed by the user immediately priorto application of the adhesive wafer to the skin. Both before and duringuse, the distal surface of the adhesive wafer can be made up of abacking layer, which can be used to attach the collecting bag to theadhesive wafer, for instance by welding. As such, the adhesive wafer maycomprise a distal backing layer and a proximal release liner, with thefirst switchable adhesive composition and the second adhesivecomposition located between the backing layer and the release liner.

Adhesives being soft or even liquid may be excellent with regard toadhesion to the skin, due to their ability to flow into themicrostructure and macrostructure of the skin. However, the texture ofsuch adhesives makes it difficult to incorporate them into ostomydevices. The adhesive may flow during storage and application and end upin undesired places.

The first switchable adhesive is contained in a recess in the device. Byhaving the first adhesive in a recess, the adhesive is in a simplemanner controlled with regard to flowing as it is contained in therecess and the device can be stored and handled without the adhesive isescaping.

By recess is herein meant a structure that is capable of containing aflowable substance, i.e. a cavity like structure with wall preventingthe liquid substance from unintended flowing away from the recess.

In embodiments, the recess is in the release liner. The release linermay be formed, for example thermoformed to comprise a recess forcontaining at least a part of the first adhesive. The recess willprevent the first adhesive from escaping from the wafer before use.

In embodiments, the recess is in the second adhesive composition. Acavity may be embossed into the second adhesive composition therebyproviding a recess for containing the first adhesive. The skin facingsurface of the first and the second adhesive composition may be flush inthe sense that the skin-facing surface of the wafer is substantiallyplanar.

In embodiments, the recess is partly in the second adhesive compositionand partly in the release liner.

In embodiments, the recess is provided by at least a part of the edgeportions of the first adhesive have been switched into a form-stabletexture. These switched parts of the first adhesive may constitute wallsof a recess for containing the adhesive. In embodiments, the switchededge portions have a width of 0.5-3 mm, such as approximately 1 mm. Therecess is bound by the walls of switched adhesive and the backing layeror the second adhesive layer.

In an aspect is provided an ostomy device including an adhesive waferfor attachment to a skin surface of a user, and a collecting bagconnected to the adhesive wafer. The collecting bag is suitable forcollecting output from the stoma of the user. The adhesive wafer has athrough-going hole for accommodating the stoma of the user. In this way,the output from the stoma ends up in the collecting bag. The adhesivewafer includes a backing layer, and a first switchable adhesivecomposition and a release liner. The first switchable adhesivecomposition is accommodated in a recess in the device.

In embodiments, the recess has a size and shape substantially equal tothe size and shape of the layer of the first switchable adhesive.

The release liner may be in contact with both the first switchableadhesive composition and the second adhesive composition.

In embodiments, the first switchable adhesive composition is having inthe first liquid state a complex viscosity |η*| below 0.4 MPa s (megaPascal-second, i.e., MPa·s); and having in the second adhesive state ahigher complex viscosity |η*| than the complex viscosity |η*| of thefirst liquid state, and having in the second adhesive state a secondrepeated peel force above 1 N.

In embodiments, the first switchable adhesive composition has an innerrim in a radial distance from the through-going hole defining an inwardboundary and an outer rim in a radial distance from the through-goinghole defining an outward boundary for in a radial distance from thehole. The part of the first adhesive being along the outer rim or edgemay be switched in order to provide a more solid and form stable barrieror wall to prevent the first adhesive from flowing. In embodiments, atleast the inner or the outer rim of the first switchable adhesive areswitched to form a recess for containing the first switchable adhesive.

In embodiments, the layer of the first adhesive may be provided withlines of switched adhesive, providing stability for the first adhesivelayer. The lines may divide the first adhesive into compartments,separated by switched walls. The switching of the adhesive along the rimand/or in lines may be done by laser or by a mold. The switched linesmay have a width of 0.5-3 mm, such as approximately 1 mm.

In an aspect is provided a method of applying an ostomy devicecomprising the steps of: providing an ostomy device comprising anadhesive wafer for attachment to a skin surface of a user, and acollecting bag connected to the adhesive wafer; the adhesive waferhaving a through-going hole for accommodating the stoma of the user; andthe adhesive wafer comprising a backing layer, a first switchableadhesive composition, a second adhesive composition, and at least onerelease liner, wherein the first switchable adhesive comprises a polymerand a switch initiator, wherein the composition can be switched from afirst liquid state to a second adhesive state by activation of theswitch initiator, wherein the device comprises a recess foraccommodating the first switchable adhesive composition, removing atleast a part of the release liner from the device, applying the adhesivewafer to the skin around the stoma, molding the first adhesive to fitaround the stoma and switching the first adhesive composition from afirst liquid state to a second adhesive state by activation of theswitch initiator.

The method may be carried out by a person other than the user to whichthe adhesive is attached. For instance, the method may be carried out bya commercial service provider assisting the user for a fee. Suchcommercial service providers exist and provide fee-based services to,e.g., ostomy users or people with wounds. The service may include theservice provider removing and applying ostomy bags for the ostomy useror removing and applying wound dressings for a person with wounds.

The method may also be carried out in order to obtain a sample of theoutput from the ostomy user or wound exudate from the person withwounds. For instance, a healthcare professional may require a stomaoutput or wound exudate sample in order to make medical decisions orgenerally assess the physical state of a user. In such cases, thehealthcare professional may order the sampling to be done by aprofessional service provider to ensure that the sampling happenscorrectly. Again, a fee-based commercial service provider would carryout the method with the aim of providing a sample to the healthcareprofessional. Such paid services exist on commercial terms and operateon a continuous and independent basis with an aim of financial gain.They are not exclusively dependent for their operation on theinstructions of the user in question. For instance, they may workdirectly under the instructions of a healthcare professional.

In embodiments, the first adhesive may be switched actively by the userfor example by exposure to light or moisture or it may switchpassively/automatically over time.

In embodiments, an active switch may be fast such as in 10 seconds. Apassive switch may be slower, for example be an on-going process fromapplication to removal.

The through-going hole may be cut to fit the stoma prior to application.In embodiments, cutting lines in the form of switched adhesive or linesof reduced thickness may be provided in order to ease the cutting.

In embodiments, the size and shape of the hole may be adapted to fit thestoma by rolling up the edges of the hole.

The texture of the first adhesive allows the user to mold the adhesiveinto a snug fit around the stoma and it is thus possible to fit thewafer to the stoma without cutting the hole precisely. When the firstadhesive is molded to fit the stoma, the adhesive may be switched toachieve a more form stable texture, securing the adhesive stays inplace.

The switching of the adhesive may alter the texture from a low cohesionto high cohesion. The low cohesion enables good flow into the structuresof the skin and good tack, whereas the high cohesion enables easyremoval of the adhesive without leaving residues on the skin.

The first switchable adhesive composition comprising a polymer and aswitch initiator, wherein the composition can be switched from a firstliquid state to a second adhesive state by activation of the switchinitiator.

In embodiments, the first adhesive composition is having in the firstliquid state a complex viscosity |η*| below 0.4 MPa s (megaPascal-second, i.e., MPa·s); and is having in the second adhesive statea higher complex viscosity |η*| than the complex viscosity |η*| of thefirst liquid state, and is having in the second adhesive state a secondrepeated peel force above 1 N.

The present inventors have found that the many requirements of anadhesive can be addressed by using a composition that can exists in atleast two different states, which have different physical properties andaddress different requirements of the adhesive. The composition can thenat some point be switched from one state to another state, therebychanging its physical properties and the characteristics associated withthese properties.

For instance, a composition may have a first state in which it quicklyand easily wets the surface to which it is to be adhered and thusachieves a sufficient adhesive attachment. The same composition may havea second state in which it very easily remains securely adhered to theskin and can be properly removed. In such a situation, the compositionin its first state could be applied to the skin. Then the compositioncould be switched to the second state, in which it would remain securelyattached.

The first state of the composition can be a first liquid state in whichthe composition is relatively fluid, i.e. has a low viscosity.

The second state can be a second adhesive state in which the compositionpossesses good adhesive qualities, for instance by exhibiting thecharacteristics of a pressure sensitive adhesive. The composition in thesecond state can be more viscous, i.e. have a higher viscosity, than thecomposition in the first state.

The composition of the first switchable adhesive can be a skin adhesivecomposition, i.e. an adhesive composition that is to be used on the skinof a person. The adhesive composition may for instance be used forattaching an ostomy device to an ostomy user.

By combining the properties of the first state and the second state intoone composition, an adhesive is obtained that is capable of quickly andeffortlessly establishing good adhesion and reliably staying adhered tothe skin. The quick and effortless adhesion is achieved by thecomposition in the first state while the reliable adherence, forinstance to skin, is achieved by the composition in the second state.

The switch is the transition from one state to another state of aswitchable composition. The duration of the switch will vary dependingon, e.g., the nature of the switch initiator and the method ofactivation of the switch initiator. Generally, the switch will be agradual process with a gradual change of physical properties of thematerial from one state to another state. In some instances, the switchwill be very fast and the physical properties will change very quickly,e.g. within seconds, to those of the second state. In other instances,the switch will be slower and the change in properties will happengradually over a period of, e.g., several minutes or even hours. In someembodiments, the activation of the switch initiator comprises exposureof the switch initiator to light or moisture.

In some embodiments, the light comprises visible light and/or UV light.Visible light is defined as electromagnetic radiation with a wavelengthin the range 400-700 nm. Ultraviolet light is defined as electromagneticradiation with a wavelength in the range 10-400 nm.

In some embodiments, the exposure to light has a duration of 10-60seconds.

For instance, the exposure to light may be less than 60 minutes, lessthan 30 minutes, less than 10 minutes, less than 5 minutes, less than 4minutes, less than 3 minutes, less than 2 minutes, less than 1 minute,less than 45 seconds, less than 30 seconds, less than 15 seconds, lessthan 10 second, less than 5 seconds, 1-10 seconds, 10-30 seconds, 10-60seconds, 30-60 seconds, 1-2 minutes, 2-3 minutes, 3-4 minutes, or 4-5minutes.

In some embodiments, the activation of the switch initiator comprisesuptake of moisture, e.g. from the surrounding air, into the adhesivecomposition.

The fast and effective adhesion to the skin effected by the switchableadhesive composition further leads to prevention of leakage of outputfrom the ostomy.

Leakage is when ostomy output makes its way to the skin and clothesoutside the ostomy device. This can of course also be damaging to theskin and the adhesive and is, obviously, also problematic to the user interms of discomfort and smell. Leakage typically results from ostomyoutput having first leaked into the adhesive and then through theadhesive to the outside, or into the space between the skin and theadhesive and then to the outside. As such, preventing leakage betweenthe adhesive and the skin as well as into the adhesive will also preventmost types of leakage outside of the ostomy device. A special kind ofleakage is when the ostomy bag partly or entirely detaches from the skinof the user during use, thus causing the output in the collecting bag todirectly spill out. This type of leakage is best prevented by ensuring astrong a durable adhesive bond between the skin of the user and theostomy device. Also, detachment will typically be a result of theadhesive having been weakened during the course of use, for instance bybeing affected by the output. As such, ensuring a strong and enduringadhesive bond and preventing leakage will also minimize the risk of theadhesive detaching from the skin and the bag falling off.

By using a switchable adhesive composition with a pre-switch lowviscosity, a quick initial adherence between the adhesive and the skinof the user can take place as well as it is possible to mold theadhesive into a snug fit around the stoma. The low viscosity of theadhesive allows it to blend into the structure, wrinkles and folds ofthe skin to facilitate a tight-fitting adhesion to the skin. This will,already from application of the adhesive to the skin, prevent outputfrom leaking into the space between the skin and the adhesive. This isin contrast to some non-switchable pressure sensitive adhesives, whichtypically require a significant amount of time, such as 10-60 minutes,to achieve strong adhesion. By applying pressure to the pressuresensitive adhesive it is possible for the adhesive to wet and flowfaster into the skin surface, hereby obtaining a large contact area andhereby increasing the adhesive power. Some current adhesive systems forattachment of ostomy devices to the skin require a high or prolongedpressure from the user in order to sufficiently flow into and wet thesurface of the substrate. By using a switchable adhesive with an initiallow viscosity, neither a high pressure nor a long time is needed inorder to ensure a good and enduring adhesion to the skin.

The quick and effective initial bonding of the switchable adhesive isthought to be at least partly the result of the ability of theswitchable adhesive to quickly wet the skin, meaning that it willquickly flow into both the macro- and micro-structures of the skin andthereby establish a large contact surface between the adhesive and theskin. This flowing of the adhesive into the skin is a common phenomenonfor pressure sensitive adhesives, but the speed at which it happens, andhence how quickly a strong adhesive bond is formed, varies widely fordifferent compositions.

Typically, ostomy users will want to be able to move around shortlyafter having applied the ostomy device to the skin. Such movements canincrease the risk of leakage if the adhesive has not yet achieved strongadhesion to the skin. With a switchable adhesive composition the risk ofsuch leakage soon after application is reduced because of the rapidlyforming effective adhesive bond. Switching the first adhesive afterapplication to the skin may provide the adhesive with a higher viscosityand form stability as well as detachment of the wafer may be easier, dueto a higher cohesion of the adhesive.

In embodiments, the first switchable adhesive composition is in contactwith the backing layer. The first switchable adhesive composition may bedisposed on the backing layer or coated on the backing layer. By beingin contact with the backing layer, at least part of the switchableadhesive composition is close to the distal non-skin-facing surface ofthe adhesive wafer. This will make it easier to effect the switch of theswitchable adhesive composition, for instance by applying light to theswitchable adhesive composition through the backing layer. Inembodiments, the first switchable adhesive may fully cover the backinglayer or it may be disposed on a part of the backing layer. If a secondadhesive is present it may cover the remaining part of the backinglayer.

In embodiments, the release liner is in contact with both the firstswitchable adhesive composition and the second adhesive composition. Therelease liner covers the surface of the adhesive that is to be attachedto the skin of the user. As such, the surface of the adhesive that is incontact with the release liner is also the surface that will be incontact with the skin of the user during use. By having both the firstswitchable adhesive composition and the second adhesive composition formpart of the adhesive surface that comes into contact with the user'sskin, it is ensured that both adhesives can exert their respectiveeffects directly on the skin. In other words, both adhesive compositionswill be in contact with the user's skin during use.

In embodiments, the adhesive wafer has a central part adjacent to thethrough-going hole for accommodating the stoma and a peripheral partadjacent to an edge of the adhesive wafer away from the hole. The firstswitchable adhesive composition may be located at least in the centralpart of the adhesive wafer. The central part of the wafer is the partthat is closer to the through-going hole in the wafer than it is to theperipheral edge of the wafer. Typically, this will represent aring-shaped area of the adhesive wafer surrounding the hole. The centralpart will be the part of the wafer that is closest to the stoma duringuse of the ostomy device. The peripheral part is the remainder of theadhesive wafer outside the central part, i.e., the part that is closerto the peripheral edge than to the hole. Typically, the peripheral partwill also be a ring-shaped area of the adhesive wafer. The adhesive maybe in the entire peripheral part of the wafer. The second adhesive mayextend also to the central part of the adhesive wafer.

In embodiments, the first switchable adhesive composition is locatedonly in the central part of the adhesive wafer. The first switchableadhesive composition may be located as a ring-shaped element in thecentral part of the adhesive wafer, thus surrounding the stoma duringuse.

In embodiments, the second adhesive composition is located at least inthe peripheral part of the adhesive wafer. The second adhesivecomposition may be in the entirety of the peripheral part or only inpart of the peripheral part of the wafer. The second adhesivecomposition may extend into the central part of the wafer.

In embodiments, the releaser liner is in contact with the first adhesivecomposition in the central part of the adhesive wafer. In this manner,the first adhesive will be in contact with the skin surrounding thestoma during use. This will allow the first adhesive to be molded toseal around the stoma. In embodiments, the backing layer is suitablyelastic, i.e. it has a low modulus, enabling the adhesive constructionto conform to the skin movement and provide comfort when using it. Thebacking layer may have a structured surface to improve the adhesionbetween the adhesive and the backing layer. The backing layer may be anon-woven or a non-woven-film laminate. The backing layer may be apolymer film. The backing layer may comprise polyurethane. The thicknessof the backing layer is dependent on the type of backing layer used. Forpolymer films, such as polyurethane films, the overall thickness may bebetween 10 to 100 micrometers, such as between 20 to 50 micrometers,such as about 20-30 micrometers.

The release liner may be of any material known to be useful as a releaseliner for medical devices. For instance, the release liner may be in theform of a polymer film, foil, or paper, having release properties thatenable the adhesive to be released easily from the liner. Suchproperties may be inherent in the material or the layer may besiliconized, coated with a low surface tension coating, or subjected toother appropriate surface modifications. Release liners are in generalmade on a mechanically stiff backing such as paper, polyethylene,polypropylene, or polyethylene terephthalate. This stiffness willsupport the adhesive wafer when applying the collecting device. Therelease lines may be thermoformed into a form stable shape, such ashaving a recess for accommodating at least a part of the first adhesivecomposition.

In embodiments, the first switchable adhesive composition is in the formof a ring-shaped adhesive element located around the hole in theadhesive wafer and in contact with the release liner. Such a ring-shapedadhesive element could have a diameter of 30-70 mm, such as 40-70 mm,such as 50-70 mm, such as 60-70 mm. The ring-shaped adhesive elementcould for instance have a diameter of 30 mm, 40 mm, 50 mm, 60 mm, or 70mm. The ring-shaped element could have a width, i.e. the distance fromthe inner rim of the ring to the outer rim of the ring measured alongthe surface of the ring, of at least 10 mm, at least 20 mm, at least 30mm, at least 40 mm, at least 50 mm, 10-20 mm, 10-30 mm, 10-50 mm, 20-30mm, 20-40 mm, 20-50 mm, 30-40 mm, 30-50 mm, or 40-50 mm. The width ofthe element can be constant over the entire element or it may vary.

In embodiments, the second adhesive composition extends in the entirearea of the adhesive wafer. In embodiments, the second adhesivecomposition is in the form of a ring-shaped adhesive element located atthe periphery of the adhesive wafer. Such a ring-shaped second adhesiveelement could have a diameter of 50-150 mm, such as 50-120 mm, such as50-100 mm, such as 50-75 mm. The ring-shaped adhesive element could forinstance have a diameter of 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm,120 mm, or 150 mm. The ring-shaped element could have a width of atleast 10 mm, at least 20 mm, at least 30 mm, at least 40 mm, at least 50mm, at least 60 mm, at least 70 mm, at least 80 mm, at least 90 mm, atleast 100 mm, 10-20 mm, 10-30 mm, 10-50 mm, 10-100 mm, 20-30 mm, 20-40mm, 20-50 mm, 20-100 mm, 30-40 mm, 30-50 mm, 30-100 mm, 40-50 mm, 40-100mm, or 50-100 mm. The width of the element can be constant over theentire element or it may vary.

An adhesive element could also have an only roughly ring-shaped, oval,or roughly oval form. In that case, the mentioned diameters would be themaximum distance from one point on the outer edge of the element toanother point on the outer edge of the element. The adhesive element maybe asymmetric in shape.

In embodiments, the first switchable adhesive composition has a uniformthickness, i.e. the distance from one outer surface of the adhesive tothe other outer surface of the adhesive measured in a straight lineperpendicular to the surface of the adhesive. In embodiments, theuniform thickness of the first adhesive composition is at least 50micrometers, such as at least 100 micrometers, such as at least 200micrometers, such as at least 300 micrometers, such as at least 400micrometers, such as at least 500 micrometers, such as at least 750micrometers, such as at least 1,000 micrometers, such as at least 1,500micrometers, such as at least 2,000 micrometers, such as at least 3,000micrometers such as at least 4,000 micrometers. The uniform thickness ofthe first adhesive composition may be between 50 micrometers and 1,000micrometers, such as 100-500 micrometers, such as 200-400 micrometers,such as 200-300 micrometers. The uniform thickness of the first adhesivecomposition may be 50-250 micrometers, 100-250 micrometers, 250-500micrometers, 250-750 micrometers, 500-750 micrometers, 500-1,000micrometers, 500-1,500 micrometers, 500-2,000 micrometers, 1,000-1,500micrometers, 1,000-1,500 micrometers, 1,000-2,000 micrometers, or1,500-2,000 micrometers.

In embodiments, the first switchable adhesive composition has a variedthickness. In embodiments, the second adhesive composition has maximumthickness of at least 50 micrometers, such as at least 100 micrometers,such as at least 200 micrometers, such as at least 300 micrometers, suchas at least 400 micrometers, such as at least 500 micrometers, such asat least 750 micrometers, such as at least 1,000 micrometers, such as atleast 1,500 micrometers, such as at least 2,000 micrometers. The maximumthickness of the first adhesive composition may be between 50micrometers and 1,000 micrometers, such as 100-500 micrometers, such as200-400 micrometers, such as 200-300 micrometers. The maximum thicknessof the first adhesive composition may be 50-250 micrometers, 100-250micrometers, 250-500 micrometers, 250-750 micrometers, 500-750micrometers, 500-1,000 micrometers, 500-1,500 micrometers, 500-2,000micrometers, 1,000-1,500 micrometers, 1,000-1,500 micrometers,1,000-2,000 micrometers, or 1,500-2,000 micrometers, or 1,500-3000, or1,500-4,000 micrometers.

In embodiments, the second adhesive composition has a uniform thickness.In embodiments, the uniform thickness of the first adhesive compositionis at least 10 micrometers, such as at least 25 micrometers, such as atleast 50 micrometers, such as at least 100 micrometers, such as at least200 micrometers, such as at least 300 micrometers, such as at least 400micrometers, such as at least 500 micrometers, such as at least 750micrometers, such as at least 1,000 micrometers. The uniform thicknessof the first adhesive composition may be between 10 micrometers and1,000 micrometers, such as 25-500 micrometers, such as 50-500micrometers, such as 100-500 micrometers, such as 200-400 micrometers,such as 200-300 micrometers. The uniform thickness of the first adhesivecomposition may be 10-50 micrometers, 10-100 micrometers, 25-50micrometers, 25-100 micrometers, 50-100 micrometers, 50-250 micrometers,100-250 micrometers, 250-500 micrometers, 250-750 micrometers, 500-750micrometers, 500-1,000 micrometers.

In embodiments, the second adhesive composition has a varied thickness.In embodiments, the maximum thickness of the second adhesive compositionis at least 10 micrometers, such as at least 25 micrometers, such as atleast 50 micrometers, such as at least 100 micrometers, such as at least200 micrometers, such as at least 300 micrometers, such as at least 400micrometers, such as at least 500 micrometers, such as at least 750micrometers, such as at least 1,000 micrometers. The maximum thicknessof the second adhesive composition may be between 10 micrometers and1,000 micrometers, such as 25-500 micrometers, such as 50-500micrometers, such as 100-500 micrometers, such as 200-400 micrometers,such as 200-300 micrometers. The maximum thickness of the secondadhesive composition may be 10-50 micrometers, 10-100 micrometers, 25-50micrometers, 25-100 micrometers, 50-100 micrometers, 50-250 micrometers,100-250 micrometers, 250-500 micrometers, 250-750 micrometers, 500-750micrometers, 500-1,000 micrometers. In embodiments, the second adhesivecomposition is thicker in the peripheral part of the adhesive wafer thanin the central part of the adhesive wafer. In embodiments, a thicknessof the second adhesive composition in the peripheral part of theadhesive wafer is at least 120%, such as at least 150%, such as at least200%, such as at least 250%, such as at least 500% of a thickness of thesecond adhesive composition in the central part of the adhesive wafer.

In embodiments, the second adhesive composition is disposed on thebacking layer and covers the entire backing layer. The first adhesivecomposition is in the form of a ring-shaped adhesive element in thecenter of the adhesive wafer around the hole and on the skin-facingsurface of the second adhesive composition. In this manner, the secondadhesive composition will be in contact with the release liner in theperiphery of the wafer and the first adhesive composition will be incontact with the release liner in the center of the wafer. Bothadhesives will therefore be in contact with the skin of the user duringuse.

Polymer component: Acrylates

In embodiments, the composition comprises an acrylate, includingmethacrylates and their copolymers. Acrylate copolymers are especiallypreferred, e.g., alkyl acrylate copolymers.

The most commonly used monomers in polyacrylates include ethyl acrylate,butyl acrylate, ethylhexyl acrylate, hydroxyethyl acrylate, laurylacrylate, and acrylic acid. They may be used singly or in a mixture,their relative proportions in the mixture being selected depending onthe desired viscoelastic properties, glass transition temperature,compatibility etc.

The polymer may be a copolymer with one or more acrylates.Alternatively, the polymer may be a copolymer with one or more acrylatesand a free radical polymerisable vinyl moiety. Such vinyl moietiesinclude compounds such as itaconic anhydride, maleic anhydride or vinylazlactone or glycidyl methacrylate.

The polymer may be a homopolymer, a random copolymer or a blockcopolymer. The polymer may be branched or linear.

The composition may include bound-in curable moieties. Anyconventionally known unsaturated compounds, e.g. olefinic or aromaticcompounds may be used or compounds with labile groups or groups whichcan undergo free radical reactions, could be used as the curablemolecules. Photoreactive groups may also be used and include groups suchas anthracenes, cinnamates, maleimides and coumarin groups. Otherfunctional groups include carboxyl, epoxy, urethane, siloxane, amides,and hydroxyl. Mixtures of all of the above may also be used. Thebound-in curable groups may be end groups, pendant groups or may beincorporated into the backbone.

The polymer backbone may be partially cross-linked. Crosslinking can beachieved by incorporating monomers of e.g. N-methylol acrylamide,N-(iso-butoxymethylene)-acrylamide, methyl acrylamidoglycolate methylether (all 0.5-5% (w/w)) or metal chelates, e.g., acetylacetonates ofZr, Al, or Fe (up to 2% (w/w) of polymer weight), into the polymerbackbone, which then crosslinks during drying after spreading on asubstrate. Al and Ti acetylacetonates and similar compounds can also beadded after polymerization in concentrations of 0.1-2% (w/w) and used asan crosslinker through utilizing carboxylic groups in the polymerbackbone during the drying step.

Multi functional isocyanates, like toluene diisocyante (TDI), trimethylhexamethylene diisocyanate (TMDI), and hexamethylene diisocyante (HDI),can be used to chemically link hydroxylic or carboxylic functions ofdifferent polymer chains, added in concentration up to 1% (w/w).

Crosslinking can also be achieved between the carboxylic groups in thepolymer backbone and added amino resins, such as derivatives ofmelamine, benzoguanamine, glycoluril, and urea, e.g., hexamethoxymethylmelamine, methoxymethyl methylol melamine, methoxymethyl ethoxymethylbenzoguanamine, tetrabutoxymethyl glycoluril, butoxymethyl methylolurea, in concentrations up to 6% (w/w).

The above mentioned cross-linking can also be achieved usingpolycarbodiimides or multifunctional propylene imines.

It is also possible to blend one or more polymers having high cohesivestrength with one or more polymers having low cohesive strength in orderto achieve the desired balance.

The polymer will most often be soluble in, and hence commerciallysupplied as solutions in, organic solvents such as ethyl acetate,hexane, toluene, acetone, etc. Preferably, the polymer isnon-water-soluble.

The polymer may be a commercially available PSA or PSA precursor, e.g.acResin A 204 UV, acResin A 260 UV (BASF), Aroset 1450-Z-40, Aroset S390(Ashland), GMS 788, GMS 1753 (Henkel).

The polymer may include curable molecules which may be low molecularweight monomers or oligomers. In the broadest sense, any conventionalknown unsaturated compounds, or compounds with labile groups or groupswhich can undergo free radical reactions, could be used as the curablemolecules. Preferred examples, used alone or in mixtures, are curablemolecules such as acrylic acid esters or methacrylic acid esters ofalcohols, glycols, pentaerythritol, trimethylpropane, glycerol,aliphatic epoxides, aromatic epoxides including bisphenol A epoxides,aliphatic urethanes, silicones, polyesters and polyethers, as well asethoxylated or propoxylated species thereof.

The curable molecules can have more than one unsaturated or reactivesite. With more than a single functionality they enable chain extension.With multiple functionalities of three or greater they are able to formcrosslinked three-dimensional polymeric networks. Examples include CN925(Arkema), Ebecryl 870 (Allnex).

Preferably, the curable molecules and the polymer are soluble in eachother when in the dry state, i.e., in the absence of a solvent.Alternatively, in the case that the polymer and the curable moleculesare not mutually soluble in each other when dry, or are only partlymutually soluble, they are uniformly dispersed in the composition.

In embodiments, the composition comprises a silicone polymer.

Moisture curing materials are polymeric materials that change from aliquid to a solid state when exposed to moisture. When these materialssolidify, they are capable of sustaining deforming forces.

Moisture curing materials may comprise several components including areactive polymer, a catalyst, a viscosity modifier, a crosslinker, and awater scavenger. The function of the reactive polymer together with acatalyst and a crosslinker is to form a polymer network upon exposure tomoisture. This event makes moisture curing materials change from aliquid to a solid state. This may be referred to as “switching” or“curing”.

The function of a viscosity modifier is to tune the viscosity to fulfilthe requirements of each application. The function of the waterscavenger is to prevent unintended curing in the container.

Moisture curing materials may be in one part or in two parts. In case ofone-part moisture curing materials, all components may be mixed andstored in a single container until use. Curing starts only once themoisture curing material is open and exposed to moisture. On the otherhand, in case of two-component systems, reactive components are isolatedfrom each other in different containers during storage, and come intocontact only at the time of use. The reactive components are mixedshortly before use. Curing starts as soon as the reactive components aremixed.

The change of properties from liquid to an adhesive state in moisturecuring materials is usually based on condensation cure chemistry.

There is a variety of base polymers with different backbone chemistries,which can lead to condensation cure. Silicone polymers may be used incondensation cure compositions. In order to react via condensation cure,silicones may be terminated with hydroxyl groups in both ends. In thepresence of a multifunctional silane, which acts both as cross-linkerand water scavenger, catalyst and moisture, hydroxyl terminatedsilicones will cure. The reactivity of silanol groups vary with thenumber of electron-withdrawing groups substituents on the silicon atom.

The substituents on the multifunctional cross-linker is a relevantparameter, which may affect the cure speed. A trifunctional,tetrafunctional, and even higher functional oligomeric and polymericcross-linkers can be employed. In embodiments, different substituents,such as methyl, ethyl, and vinyl groups may be used. Examples oftrifunctional cross-linkers based on alkoxy groups include methyltrimethoxy silane and methyl triethoxy silane. In addition to alkoxy,acetoxy, oxime, amine, amide, and enoxy cure systems are available.

The curing systems may be adapted to different applications depending onby-products of the curing process. For example, for ostomy care,by-products should be non-toxic and should not have a bad smell.

A suitable condensation cure catalyst is chosen depending on thechemistry of the multifunctional silane. Titanates are employed withalkoxy, amide, or mime systems, whereas tin catalysts may be added toacetoxy, oxime, and amine cure formulations. In embodiments, thetitanate catalyst used is selected from tetraalkoxy titanates andchelated titanates. Tetraalkoxy titanates are the more catalyticallyactive species.

The rate of condensation curing depends on the crosslinking agent (itsfunctionality, concentration and chemical structure), the type ofcatalyst, and the relative humidity of the environment.

Moisture curing formulations are interesting materials for applicationsin ostomy care, either as an accessory or as a full device. Somerelevant features to consider for moisture curing compositions to beused in ostomy care:

-   -   Safe to use on skin: Moisture curing formulations should be        non-toxic before and after cure since they will meet skin.    -   Adhesion to skin: Moisture curing formulations should adhere to        skin before and after cure. Otherwise, these materials will        provide a weak interface between the skin and ostomy care        device.    -   Handle moisture from body: Ostomy care products should handle        moisture, which comes from skin, output, and sweat. Otherwise,        water remaining on the skin weakens the adhesion.    -   Stable during storage: Moisture curing formulations should be        stable during storage in the factory and transportation, but        also in the hands of the users before use. Depending on the        geographic location, the temperature, and relative humidity of        the environment changes. Moisture curing formulations should be        stable enough not to cure when exposed to temperatures relevant        to storage, transportation, and use situation. In addition, they        should be packaged in a way that the moisture cannot diffuse        into their container.

Commercially available moisture curing formulations used, e.g., in theconstruction industry are typically not safe for use on skin. Thecommercially available “Trio Silken Stoma Gel” from Trio Healthcare isapproved for use on skin. However, Trio Silken Stoma Gel has majorshortcomings, since it does not adhere to skin and does not absorb bodyfluids.

Typically, moisture-curing materials for ostomy care applicationsinclude a reactive component to cure, a water absorbing component toabsorb moisture from the body, and an adhesive component to enable skinadhesion. A straightforward strategy to obtain skin adhesives based onmoisture curing is to mix unreactive polymers with adhesive characterwith reactive components, which on their own do not adhere to skinbefore and after cure. Such materials will be adherent to skin beforeand after cure. Employing such a strategy opens the opportunity of usinga variety of reactive materials available in other industries afternecessary modifications to fulfil the bio-safety requirements for skinapplication. As the water-absorbing component, e.g., naturalhydrocolloids or synthetic hydrophilic polymers can be used.

Adding a water-absorbing component to moisture curing formulations maylead to additional considerations, since some water may be present innatural hydrocolloids or synthetic hydrophilic polymers, which may causeundesired effects with regard to both curing speed and storagestability. A way to minimize such effects is careful drying of waterabsorbing components prior to their addition to moisture curingformulations.

A switch initiator is a component of a switchable composition, whichcomponent upon activation is able to trigger a switch of the switchablecomposition.

In embodiments the switch initiator comprises or consists of a freeradical generating switch initiator. The free radical generating switchinitiator may be a photoinitiator. Different photoinitiator systemsexist. Photoinitiator systems can be (a) low molecular weight singlecomponent, (b) low molecular weight multiple component, (c) polymericsingle component, or (d) polymeric multi-component. These systems can bebuilt using chemicals named below and/or polymers containing thesefunctionalities.

In the present invention, a photoinitiator is defined as a moiety which,on absorption of light, generates reactive species (ions or radicals)and initiates one or several chemical reactions or transformation. Insome embodiments a preferred property of the photoinitiator is goodoverlap between the UV light source spectrum and the photoinitiatorabsorption spectrum. In some embodiments, a desired property is a minoror no overlap between the photoinitiator absorption spectrum and theintrinsic combined absorption spectrum of the other components in thecomposition.

Suitably, the photoinitiator moieties are pendant on the polymer. Thismeans that they are attached to the polymer at points other than at thepolymer ends, thus making it possible to attach more than twophotoinitiator moieties to a single polymer.

The photoinitiator moieties of the invention may independently becleavable (Norrish Type I) or non-cleavable (Norrish Type II). Uponexcitation, cleavable photoinitiator moieties spontaneously break downinto two radicals, at least one of which is reactive enough to abstracta hydrogen atom. Benzoin ethers (including benzil dialkyl ketals),phenyl hydroxyalkyl ketones and phenyl aminoalkyl ketones are examplesof cleavable photoinitiator moieties.

In embodiments, the photoinitiator is efficient in transforming lightfrom the UV or visible light source to reactive radicals which canabstract hydrogen atoms and other labile atoms from polymers, and henceeffect covalent cross-linking. Optionally, amines, thiols and otherelectron donors can be either covalently linked to a polymericphotoinitiator or added separately or both. The addition of electrondonors is not required but may enhance the overall efficiency ofcleavable photoinitiators according to a mechanism similar to thatdescribed for the non-cleavable photoinitiators below.

In embodiments the photoinitiator of the invention is non-cleavable(Norrish Type II). Non-cleavable photoinitiators do not break down uponexcitation, thus providing fewer possibilities for the leaching of smallmolecules from the composition. Excited non-cleavable photoinitiators donot break down to radicals upon excitation, but abstract a hydrogen atomfrom an organic molecule or, more efficiently, abstract an electron froman electron donor (such as an amine or a thiol). The electron transferproduces a radical anion on the photoinitiator and a radical cation onthe electron donor. This is followed by proton transfer from the radicalcation to the radical anion to produce two uncharged radicals; of thesethe radical on the electron donor is sufficiently reactive to abstract ahydrogen atom.

Benzophenones and related ketones such as thioxanthones, xanthones,anthraquinones, fluorenones, dibenzosuberones, benzils, and phenylketocoumarins are examples of non-cleavable photoinitiators. Most amineswith a C—H bond in a-position to the nitrogen atom and many thiols willwork as electron donors. An advantage of using Norrish Type II asopposed to Type I photoinitiators is fewer generated by-products duringphotoinitiated reactions. As such benzophenones are widely used. Whenfor example α-hydroxy-alkyl-phenones dissociate in a photoinitiatedreaction, two radicals are formed, which can further dissociate andpossibly form loosely bound unwanted aromatic by-products.

Self-initiating photoinitiator moieties may also be used. Upon UV orvisible light excitation, such photoinitiators predominantly cleave by aNorrish type I mechanism and cross-link further without any conventionalphotoinitiator present, allowing thick layers to be switched. Recently,a new class of β-keto ester based photoinitiators has been introduced.

In some embodiments, the switch initiator comprises at least twodifferent types of photoinitiators. The absorbance peaks of thedifferent photoinitiators are at different wavelengths, so the totalamount of light absorbed by the system increases. The differentphotoinitiators may be all cleavable, all non-cleavable, or a mixture ofcleavable and non-cleavable. A blend of several photoinitiator moietiesmay exhibit synergistic properties. In some embodiments the switchinitiator comprises a mix of different photoinitiators, such as two,three, four, or five different photoinitiators.

Examples of photoinitiators absorbing in the 200-400 nm range includeα-hydroxyketone, benzophenone, benzophenone derivatives,benzophenone/α-hydroxyketone, phenylglyoxylate, benzyldimethyl-ketal,aminoketone, acylphosphine oxide derivatives, mono acyl phosphine(MAPO), MAPO/α-Hydroxyketone, bis acyl phosphine (BAPO), BAPOdispersion, BAPO/α-hydroxyketone, phosphine oxide, metallocene, ioniumsalt, thioxanthone derivatives, mixture of triarylsulphoniumhexafluorophosphate salts in propylene carbonate, mixture oftriarylsulphonium hexafluoroantimonate salts in propylene carbonate,camphorquinone derivatives, benzil derivatives, anthraquinonederivatives, benzoin ether derivatives, and polysilanes.

Specific examples of photoinitiators include2-Benzyl-2-(dimethylamino)-4′-morpholinobutyrophenone,2-Methyl-4′-(methylthio)-2-morpholinopropiophenone, (Benzene)tricarbonylchronium, (Cumene)cyclopentadienyliron(II)hexafluorophophate,dibenzosuberenone, ferrocene, and methylbenzoylformate.

Other examples include aromatic ketones useful in the 200-400 nm range,e.g. acetophenone; camphorquinone+iodonium salt+silane (which may beuseful in obtaining efficient photoinitiation in air); peroxides, e.g.benzoyl peroxide; and azo compounds, e.g. 2,20-azobisisobutyronitrile.

In the >400 nm range examples of photoinitiators include carbazolederivatives, metallocene, thioxanthone derivatives, camphorquinonederivatives, benzil derivatives, titanocenes, anthraquinone derivatives,acylphosphine derivatives, keto-coumarins, xanthenic dyes (e.g.erythhrosin B), thioxanthone derivatives (e.g. 2-chlorothioxanthone,2-isopropylthioxanthone, 2-mercaptothioxanthone, thioxanthone aceticacid derivatives) optionally in combination with amines, andbenzophenones optionally in combination with amines.

In embodiments the switch initiator comprises or consist ofbis(.eta.5-2,4-cylcopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium (Ciba Irgacure 784).

In embodiments, the second adhesive composition comprises a polymercomprising monomer units selected from the group consisting of styrene,isoprene, butadiene, ethylene, and butylene.

In embodiments, the second adhesive composition comprises a styreneblock co-polymer.

In embodiments, the second adhesive composition comprises a styreneblock co-polymer selected from the group consisting ofstyrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS),styrene-isobutylene-styrene (SIBS), andstyrene-ethylene/butylene-styrene (SEBS).

In embodiments, the second adhesive composition comprises a polyethylenecopolymer.

In embodiments, the second adhesive composition comprises a polyethylenecopolymer selected from the group consisting of ethylene vinyl acetate,ethylene vinyl acetate carbon monoxide, ethylene butyl acetate, ethylenevinyl alcohol, ethylene butyl acrylate, ethylene butyl acrylate carbonmonoxide, and combinations thereof.

In embodiments, the second adhesive composition comprisespolyisobutylene (PIB).

In embodiments, the second adhesive composition comprises absorbentmaterial. In embodiments, the second adhesive composition compriseswater absorbent material.

In embodiments, the second adhesive composition comprises absorbentmaterial selected from the group consisting of hydrocolloids,microcolloids, salt, and super absorbent particles.

In embodiments, the second adhesive composition comprises an absorbentmaterial in an amount of 1-60% (w/w) of the composition.

For instance, the second adhesive composition comprises an absorbentmaterial in an amount of 1-40% (w/w) or 1-20% (w/w) or 20-40% (w/w) or20-60% (w/w) or 40-60% (w/w) or 25-50% (w/w) of the composition.

In embodiments, the absorbent material is selected from hydrocolloid,water soluble salt, mono, di- and oligosaccharides, sugar alcohols,polypeptides, organic acids, inorganic acids, amino acids, amines, urea,super absorbent particles such as polyacrylic acid, glycols such aspolyethylene glycol, fumed silica, bentone, and mixtures thereof.

In embodiments, the hydrocolloid is selected from guar gum, locust beangum, pectin, potato starch, alginates, gelatine, xantan or gum karaya,cellulose derivatives, salts of carboxymethyl cellulose, sodiumcarboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose,hydroxyethyl cellulose, sodium starch glycolate, polyvinylalcohol, andmixtures thereof.

In embodiments, the water soluble salt is selected from NaCl, CaCl₂,K₂SO₄, NaHCO₃, Na₂CO₃, KCl, NaBr, NaI, KI, NH₄Cl, AlCl₃, CH₃COONa,CH₃COOK, HCOONa, HCOOK, and mixtures thereof.

In embodiments, the adhesive composition may comprise ingredients suchas tackifiers, extenders, non-reactive polymers, oils (e.g.polypropyleneoxide, ethyleneoxide-propyleneoxide copolymers, mineraloil), plasticizers, fillers, and surfactants.

One element in forming the adhesive bond is the flow of the adhesivecomposition into the micro- and macro-structure of the substrate. Thebetter the adhesive composition is able to flow into, i.e. wet, thesubstrate, the larger the adhesive contact area obtained. A largecontact area between the adhesive and the substrate will lead toimproved adhesion. Wetting of a substrate by an adhesive composition isdependent on the characteristics of the composition as well as upon,e.g., time, temperature, and pressure. In relation to wetting of asubstrate, a central characteristic of an adhesive composition is theviscosity, measured herein as the complex viscosity |η*|.

In embodiments, the switchable adhesive composition has a complexviscosity |72 *| below 400,000 Pa s, 300,000 Pa s, 200,000 Pa s, below150,000 Pa s, below 100,000 Pa s, below 75,000 Pa s, below 50,000 Pa s,below 25,000 Pa s, below 10,000 Pa s, below 5,000 Pa s, below 1,000 Pas, below 500 Pa s, below 250 Pa s, below 100 Pa s, below 50 Pa s, orbelow 10 Pa s measured as described herein. In embodiments, theswitchable adhesive composition has a complex viscosity |η*| of 10-50 Pas, 50-100 Pa s, 100-250 Pa s, 250-500, Pa s, 500-1,000 Pa s, 1,000-5,000Pa s, 5,000-10,000 Pa s, 10,000-25,000 Pa s, 25,000-50,000 Pa s,50,000-75,000 Pa s, 75,000-100,000 Pa s, 100,000-150,000 Pa s,150,000-200,000 Pa s, 200,000-300,000 Pa s, 300,000-400,000 Pa s,400,000-500,000 Pa s, 10-100 Pa s, 100-1,000 Pa s, 1,000-10,000 Pa s,10,000-100,000 Pa s, or 100,000-500,000 Pa s.

Complex viscosity is a measure of the resistance to gradual deformationof a given liquid state composition. Generally, the lower the viscosity,the more quickly the composition will be able to wet a rough surface byflowing into the small structures of the surface, such as themicrostructure of skin.

In the present context, a relatively low complex viscosity isadvantageous in that it will lead to the composition more easily andquickly flowing into the contour of the skin.

An advantage of this low viscosity is that the adhesive in the firststate will be able to easily and quickly flow into, i.e. wet, themicrostructure of the skin as well as larger irregularities, such asscar tissue and wrinkles. This means that a large contact surfacebetween the adhesive and the skin is quickly established and that a goodadhesive bond between the skin and the adhesive is quickly obtained.

In embodiments, the complex viscosity of the switchable adhesivecomposition after switch is at least 2 times, such as at least 5 times,such as at least 10 times, such as at least 20 times, such as at least50 times, such as at least 100 times, such as at least 1,000 times, suchas at least 10,000 times higher than the complex viscosity of theswitchable adhesive composition before switch.

Measurement Methods

Dynamic Mechanical Analysis (DMA) and Determination of Complex Viscosity|η*|

The parameter complex viscosity 10 was measured as follows by afrequency sweep. The adhesives were pressed into a plate of 1 mmthickness. A round sample of 25 mm in diameter was cut out and placed ina Haake RheoStress 6000 rotational rheometer from Thermo Scientific. Thegeometry applied was parallel plates 25 mm and the shear stress wasfixed at 5556 Pa and a gap size of 0.9-1.05 mm was applied to the samplein the beginning of the measurement to obtain a normal force ofapproximately 5 N. The measurements were carried out at 32° C. For thecomplex viscosity |η*| the value measured at a frequency of 0.01 Hz wasused.

Moisture Vapour Transmission Rate

Moisture vapour transmission rate (MVTR) is measured in grams per squaremeter (g/m²) over a 24 hours period using an inverted cup method.

A container or cup that was water and water vapour impermeable having anopening of Ø35 mm was used. 20 mL saline water (0.9% NaCl indemineralised water) was placed in the container and the opening wassealed with the test adhesive mounted on a highly permeable polyurethane(PU) backing film (BL9601 foil from Intellicoat). The container wasplaced into an electrically heated humidity cabinet and the container orcup was placed upside down, such that the water was in contact with theadhesive. The cabinet was maintained at 32° C. and 15% relative humidity(RH).

The weight loss of the container was followed as a function of time. Theweight loss was due to water transmitted through the adhesive and/orfilm. This difference was used to calculate the MVTR of the testadhesive film. MVTR was calculated as the weight loss per time dividedby the area of the opening in the cup (g/m²/24 h).

The MVTR of a material is a linear function of the thickness of thematerial. Thus, when reporting MVTR to characterize a material, it isimportant to inform the thickness of the material which MVTR wasreported. We used 150 μm as a reference. If thinner or thicker sampleswere measured, the MVTR was reported as corresponding to a 150 μmsample. Thus a 300 μm sample with a measured MVTR of 10 g/m²/24 h wasreported as having MVTR=20 g/m²/24 h for a 150 μm sample because of thelinear connection between thickness of sample and MVTR of sample.

Finally, we noted that by using this method, we introduced an error byusing a supporting PU film. Utilizing the fact that the adhesive/filmlaminate was a system of two resistances in series eliminated the error.When the film and the adhesive are homogeneous, the transmission ratemay be expressed as:

1/P(measured)=1/P(film)+1/P(adhesive).

Hence, by knowing the film permeability and thickness of the adhesive,it was possible to calculate the true permeability of the adhesive,P(adhesive), using the following expression:

P(adhesive)=d(adhesive)/150 μm*1/(1/P(measured)−1/P(film))

where d(adhesive) was the actual measured thickness of the adhesive andP(film) was the MVTR of the film without any adhesive on and P(measured)was the actual measured MVTR.

Moisture Absorption

Samples were prepared by thermoforming to a 0.5 mm thick adhesive filmbetween two release liners. With a punching tool, samples were punchedout. Sample size was 25×25 mm. The release liners were removed. Thesamples were glued to an object glass and placed in a beaker withphysiological salt water and placed in an incubator at 37° C.

The sample was weighed at the outset (M(start)) and after 2 hours (M(2hours). Before weighing, the object glass was dried off with a cloth.For a 25×25 mm sample the area was 6.25 cm² (the surface edges were leftout of the area). The moisture absorption may be calculated as: Waterabsorption after 2 hours=(M(2 hours)−M(start))/6.25 cm². The result isin the unit g/cm² per 2 hours.

Peel Test

Substrate for Peel Test and Liquid Media.

The substrate used to simulate real use is skin.

The peel liquid media is a 4% hand soap solution in saline.

Peel Setup

In order to simulate a leakage propagation in a peel measurement, a lowand constant peel angle is chosen. This peel setup has a constant peelof 40 degrees and constant peel load of 500 g. The peel extension ismeasured with time. Different dwell times (time from applying theadhesive to the skin until test start) are used in order to observe theinstant adhesion properties of a second adhesive as well as a switchableadhesive as described herein. Peel experiments are done at ambienttemperature, approximately 20° C.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following detailed description, reference is made to theaccompanying drawings. The drawings form a part of this specificationand illustrate exemplary embodiments for practicing the invention.Directional terminology, such as “top,” “bottom,” “front,” “back,”“leading,” “trailing,” etc., is used with reference to the orientationof the Figure(s) being described. Because components of embodiments canbe positioned in a number of orientations, the directional terminologyis used for purposes of illustration and is in no way limiting. It is tobe understood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope of theinvention. The detailed description describes examples for practicingthe invention and is not to be read to limit the scope of the invention.The scope of the invention is defined by the attached claims.

Embodiments, and features of the various exemplary embodiments describedin this application, may be combined with each other (“mixed andmatched”), unless specifically noted otherwise.

In FIG. 1 is shown a cross-section of an adhesive wafer for an ostomydevice. For simplicity, collection bag and/or coupling for attachingsuch bags have been omitted in the drawing. The wafer comprises abacking layer 1 coated on the skin-facing surface with a second adhesive3. A first switchable adhesive 2 is provided at the central portion ofthe wafer, surrounding a through-going hole 5 for accommodating a stoma.A release liner 4 is covering the skin-facing surface of the waferbefore application. The release liner 4 is provided with a form stablerecess for containing the first adhesive 2.

FIG. 2 is a cross-section of shown a wafer comprising a backing layer 1being coated on the skin-facing surface with a second adhesive 3. Afirst switchable adhesive 2 is provided at the central portion of thewafer, surrounding a through-going hole 5 for accommodating a stoma. Arelease liner 4 is covering the skin-facing surface of the wafer beforeapplication. The central portion of the second adhesive 3 is providedwith a recess for containing the first adhesive 2. The skin-facingsurface of the wafer is substantially planar.

In FIG. 3 is a cross-section of shown a wafer where the both the secondadhesive 3 and the release liner 4 are provided with a recess forcontaining the first adhesive 2.

In FIG. 4 is a cross-section of shown a wafer applied to the skinsurrounding a stoma 5. The release liner is removed and the firstadhesive 2 has been molded to fit around the stoma 5.

In FIG. 5 is shown an embodiment with a backing layer 1, a firstswitchable adhesive layer 2 and a release liner 4. Along the edgeportions 6, the adhesive has been switched into a more form stabletexture, thereby preventing the adhesive to flow out of the wafer.

In FIG. 6 is shown an embodiment with a backing layer 1, a firstswitchable adhesive layer 2 and a release liner 4. Along the edgeportions 6, and at points 7 in the central portion of the first adhesivelayer, the adhesive has been switched into a more form stable texture,thereby preventing the adhesive to flow out of the wafer. The switchedpoints or lines 7 in the centre may divide the adhesive 2 into smallercompartments.

In FIG. 7 is shown an embodiment with a backing layer 1, a firstswitchable adhesive layer 2 at the central portion of the wafer andsecond adhesive 3 at the peripheral portion of the wafer and a releaseliner 4. Along the edge portions 6, the adhesive 2 has been switchedinto a more form stable texture, thereby preventing the adhesive 2 toflow out of the wafer.

EXAMPLES

Sample 1

An Adhesive Wafer with Full Cover of Switchable Adhesive

The adhesive wafer consist of a backing layer (DOW Saranex 630G), coatedwith a switchable adhesive (Composition: 74% BASF acResin A 260 UV with1% photoinitiator* and 25% hydrocolloids**) with a thickness of 1 mm anda round geometry of 110 mm, and a siliconiced release liner (0.11 mmPPB,1803 from Hutamaki). *Photoinitiator chemistry: Irgacure 784photoinitiator from Ciba,Bis(.eta.5-2,4-cylcopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium).**Hydrocolloid mixture: 25% hydrocolloids, (10% (w/w) pectinLM CG, CP Kelco, 20% (w/w) Akucell AF288, Akzo Nobel, 30% (w/w) PBgelatine, PB Gelatins and 40% (w/w) Guar gum FG-20, Hercules Corp.).

The wafer is intended to have paste like properties and changed adhesioncharacteristics from a moldable paste texture to a form stable adhesivetexture when switched.

Sample 2

An Adhesive Wafer with Switchable Adhesive at the Central Portion

The adhesive wafer consist of a backing layer (DOW Saranex 630G), a fullcover adhesive based on a standard hyderocolloide adhesive*** with athickness of 1 mm and a round geometry of 110 mm, a switchable adhesive(Composition: 74% BASF acResin A 260 UV with 1% photoinitiator* and 25%hydrocolloids**) of 2 mm thickness at the central portion and a roundgeometry with a diameter of 70 mm and a siliconiced release liner (0.11mm PPB,1803 from Hutamaki). A second adhesive*** is provided at theperipheral portion and over the distal portion of the switchableadhesive. ***((10% (w/w) Kraton 1161, from Kraton polymers, 40% OoppanolB12 from BASF 5% (w/w) pectin LM CG, CP Kelco, 10% (w/w) Akucell AF288,Akzo Nobel, 15% (w/w) PB gelatine, PB Gelatins and 20% (w/w) Guar gumFG-20, Hercules Corp). the components are mixed for 20 min in a z bladeAustin 300 g mixer for 20 min).

The first adhesive was intended to have paste like properties and willchange adhesion characteristics from moldable paste texture to a formstable adhesive texture when switched. The peripheral adhesive will notchange state.

The samples were applied to skin the adhesive properties investigated bya peel test. As can be seen from Table 1, the switchable adhesiveseparates during peel when it is not switched, in a cohesive break (theadhesive is ruptured and residues remain on both the wafer and the skin.

TABLE 1 Adhesion properties: Fracture type when removed Fracture typewhen removed from skin**** from skin**** Before switching the adhesiveAfter switching the adhesive Example 1 Cohesive break in paste Adhesivebreak Example 2 Cohesive break in paste Adhesive break (center),(center), Adhesive break (rim) Adhesive break (rim) ****Adhesives stayson skin 10 min before removal.

As an alternative examples of a switchable adhesive, amoisture-switchable adhesive could be used. A moisture-switchableadhesive could, for instance, be one of the following:

Moisture Composition 12: Mixed Moisture-Switchable Silicone Adhesivewith 10% Mixed Hydrocolloids

Trio Silken (18 g, 36 wt %, Trio Healthcare) was mixed with a mixture ofhydrocolloids (5 g, 10 wt %) using Speedmixer at 3000 rpm for 3 minutes.The hydrocolloid mixture consists of carboxymethyl cellulose (20 wt %),guar gum (40 wt %), gelatin (30 wt %) and pectin (10 wt %). Anunreactive silicone polymer, BioPSA (27 g, 54 wt %, Dow Corning 7-4560)was added to the mixture, and the mixture was mixed using Speedmixer foradditional 3 minutes at 3000 rpm. The resulting mixture was coated on apolyurethane Biatain film (30 μm) using an applicator. For the switchexperiments, this composition was switched in either an oven at 32° C.,or in a humidity cupboard (Binder KBF) at 32° C. and 50% relativehumidity.

Viscosity measured before switch: 351 Pa s at 0.01 Hz.

Moisture Composition 17: Mixed Moisture-Switchable Silicone Adhesivewith 40% Dried Mixed Hydrocolloids

Trio Silken (12 g, 24 wt %, Trio Healthcare) was mixed with a mixture ofhydrocolloids (20 g, 40 wt %) using Speedmixer at 3000 rpm for 3minutes. The hydrocolloid mixture consists of carboxymethyl cellulose(20 wt %, Akucell AF 2881, Akzo Nobel), guar gum (40 wt %, guar gumFG-200, Nordisk Gelatine), gelatin (30 wt %, gelatin UF220, PB GelatinsGmbH) and pectin (10 wt %, LM 12 CG-Z/200, CP Kelco). The hydrocolloidswere dried at 80° C. before being added to the formulation until theyreached a water content of 2.43 wt %. An unreactive silicone polymer,BioPSA (18 g, 36 wt %, Dow Corning 7-4560) was added to the mixture, andthe mixture was mixed using Speedmixer for additional 3 minutes at 3000rpm. The resulting mixture was coated on a film using an applicator, andthe film was cured in an oven at 32° C. with a relative humidity of 50%before testing.

Viscosity measured before switch: 2366 Pa s at 0.01 Hz.

1. An ostomy device comprising an adhesive wafer for attachment to askin surface of a user, and a collecting bag connected to the adhesivewafer; the adhesive wafer having a through-going hole for accommodatingthe stoma of the user; and the adhesive wafer comprising a backinglayer, a first switchable adhesive composition, a second adhesivecomposition, and at least one release liner, wherein the firstswitchable adhesive comprises a polymer and a switch initiator, whereinthe composition can be switched from a first liquid state to a secondadhesive state by activation of the switch initiator, wherein the devicecomprises a recess for accommodating the first switchable adhesivecomposition.
 2. Ostomy device according to claim 1, wherein the recessis in the release liner.
 3. Ostomy device according to any of thepreceding claims, wherein the recess is partly in the second adhesivecomposition and partly in the release liner.
 4. Ostomy device accordingto any of the preceding claims, wherein the recess is in the secondadhesive composition.
 5. Ostomy device according to claim 4, wherein theskin facing surface of the first and the second adhesive composition areflush/in line.
 6. Ostomy device according to any of the precedingclaims, wherein the recess is provided by at least a part of the edgeportions of the first adhesive have been switched into a form-stabletexture.
 7. The ostomy device according to any of the preceding claims,wherein the release liner is in contact with both the first switchableadhesive composition and the second adhesive composition.
 8. The ostomydevice according to any one of the preceding claims, wherein theadhesive wafer has a central part adjacent to the hole for accommodatingthe stoma and a peripheral part adjacent to an edge of the adhesivewafer away from the hole, and wherein the second adhesive composition islocated at least in the peripheral part of the adhesive wafer.
 9. Theostomy device according to any one of the preceding claims, wherein thefirst switchable adhesive composition is located only in the centralpart of the adhesive wafer.
 10. Ostomy device according to any of thepreceding claims, wherein the first switchable adhesive composition ishaving in the first liquid state a complex 20 viscosity |η*| below 0.4MPa s (mega Pascal-second, i.e., MPa·s); and having in the secondadhesive state a higher complex viscosity |η*| than the complexviscosity |η*| of the first liquid state, and having in the secondadhesive state a second repeated peel force above 1 N.
 11. Ostomy deviceaccording to any of the preceding claims, wherein the first switchableadhesive composition has an inner rim in a radial distance from thethrough-going hole defining an inward boundary and an outer rim in aradial distance from the through-going hole defining an outward boundaryfor in a radial distance from the hole.
 12. Ostomy device according toany of the preceding claims, wherein at least the inner or the outer rimof the first switchable adhesive are switched.
 13. Method of applying anostomy device comprising the steps of: providing an ostomy deviceaccording to any of claims 1-11, removing at least a part of the releaseliner from the device, applying the adhesive wafer to the skin aroundthe stoma, molding the first adhesive to fit around the stoma andswitching the first adhesive composition from a first liquid state to asecond adhesive state by activation of the switch initiator.
 14. Methodaccording to claim 12, wherein the through-going hole is cut to fit thestoma prior to application.